Sunday, 28 December 2014

German brewing in 1966 – boiling and cooling

I thought I’d best hurry through the rest of this article before I forget about it again. Also because it’s expanding the horizons of my book “Decoction!”.

The book now covers more than 150 years of German brewing, from the early 19th century right through to the 21st. Which reminds me that I’ve another unfinished series: German beer styles in 2014.

But on with the Journal of the Institute of Brewing article, in which we’ve now reached the section on boiling:

“Wort boiling still requires 90-100 min. if one intends to isomerize the hop bitter substances completely and to obtain coagulation of the protein components. Higher temperatures have not yet been used and hop extraction with special solvents is not permitted. Outside Bavaria, on the other hand, hop extracts such as Horst, Hopulux and Hopcon etc. may be used. Nevertheless, the percentage of fresh hops used in Pilsener beers is still very high. In some breweries hops are milled before use, thereby saving up to 10%, although occasionally the bitter ness of the beer is not so fine. This method is often used in connection with the cloth trub filter.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 19.

That’s interesting: a minimum of 90 to 100 minutes boiling is need to get the hot break. Mmm. I’ve definitely seen boiling times shorter than that in British breweries. Both world wars saw boiling times cut to save fuel. After 1942, Whitbread almost never boiled for as long as 90 minutes. Mostly it was 45 to 65 minutes, occasionally as long as 85 minutes. These short boiling times continued until the Chiswell Street brewery closed in the early 1970’s.

Clearly the stricter Reinheitsgebot that applied in Bavaria prevented the use of hop extracts. Pretty sure that’s no longer the case as I’m sure I’ve seen Bavarian beers with hop extract listed in the ingredients. I’m not a fan, myself. I’ve had too many beers ruined by a horrible musty hop aroma.

“One can see that the brewhouse work is still being carried out according to the old principles, although wet grinding or steam grinding and shorter lautering times have introduced genuine improvements. The heating of the coppers is now very seldom carried out directly with a coal fire; it is mostly carried out with oil burners in specially constructed heating units with 68-70% efficiency. In larger breweries hot water, fresh steam, or waste steam from machines or turbines is used.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 19.

British breweries had started using steam coils to boil wort as far back as the 19th century. It seems as if German brewers were much slower in taking the practice up. The little Franconian breweries I’ve visited mostly have direct-fired coppers, though the fuel is wood not coal.

“Wort cooling.—A fundamental change has occurred in wort cooling systems since pre-war years. With the old method of the coolingship, followed by an open upright cooler, and the use of a special fermenter for the first 24 hr., first class beers were produced. Nevertheless, when breweries were reconstructed or increased capacity was required, one did not wish to provide the large areas necessary for the conventional system, as these were often poorly utilized. As a result, numerous closed systems are being used. The changeover was not always easy, as difficulties occurred in providing sufficient oxygen for yeast reproduction, but by intensive aeration units or air-suction at the centrifuge, sufficient aeration could be guaranteed.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, pages 19 - 20.

Don’t think I’ve seen the term “coolingship” before. A slight variation on the usual direct translation of “coolship”. There was a special fermenter used for the first day of the fermentation? How odd. I can’t remember seeing one of those anywhere. Then again, I wasn’t looking for one and wouldn’t have known what one looked like.

There’s an explanation of this vessels function next:

“With the coolship the amount of cooler sludge depends on temperature. The higher the temperature of the wort, the more important is the subsequent removal of the cold trub. Frequently one still finds the use of a starting fermenter in which the cooled, pitched wort remains for 12-36 hr. This type of unit is wasteful in labour and a certain amount of useful yeast is lost; this can result in the slowing down of the subsequent main fermentation. Useful results have been obtained with cold sedimentation of the wort in closed units. During this process the hot trub often removes, or assists the removal of, the cold trub by a fining action. Following the 8 hr. of sedimentation, intensive aeration is necessary. Cold trub can also be removed by centrifuges and filters: both of these methods have been perfected. For normal bottom fermentation it is considered that only a portion of the cold trub should be removed; on the other hand, quick maturing of the beer can only be carried out with worts free of cold trub.”
Journal of the Institute of Brewing, Volume 72, Issue 1, January-February 1966, page 20.

It was all about removing the cold break from the wort. You know what it reminds me of? The dropping system as interpreted by Fullers. They generally only kept the fermenting wort in the upper round for a day before dropping to the settling square. Weird that something similar was done in Germany. Though rather than a shallow settling square, I assume German brewers used a standard fermenter.

3 comments:

Rod
said...

"That’s interesting: a minimum of 90 to 100 minutes boiling is need to get the hot break. Mmm. I’ve definitely seen boiling times shorter than that in British breweries."

Yes, you have. It is definitely possible to achieve the hot break in 75 minutes.Also, you are right about breweries all over Germany cheating by using hop extract, and also that you can often taste it and it's not good.Lastly, I wish to order my copy of the updated Decoction now please. As I already have the first edition do I qualify for a discount?

There are different kinds of hop extract. The ones approved under RHG may contain only 100% hop material. They may also only be used in the boil – not e.g. to top up bitterness post-fermentation as is sometimes done elsewhere.

This is sometimes misinterpreted to argue that the RHG prohibits dry-hopping, which is nonsense.